Frequency control strategy for wind-thermal-bundled power system with HVDC line

For the uneven resources distribution in China, large amounts of wind power has to be transmitted to load centers over long distance. Therefore, wind-thermal-bundled (WTB) power system transmitted by High Voltage Direct Current (HVDC) lines has become an important development mode. Wind energy with randomness and fluctuation imposes great burden on frequency stability of power system sending-end. The frequency characteristic of this new kind of system is discussed in this paper. With the integration of large-scale wind power, parameters for primary frequency regulation (PFR) of thermal units should be adjusted. With consideration of HVDC modulation functions, the coordinated frequency control strategies of HVDC systems and thermal units are proposed. Simulations are carried out based on WTB equivalent system of Northeast China. Results show that the proposed control strategies can effectively improve the frequency stability of WTB sending-end system.